THE SENSE ORGANS 171 



leaf patterns of equal size. Draw from left to right with a "free hand" 

 motion of the arms, produced by simultaneous impulses directed equally 

 to the two sides. Note the relative size and position of the figures. 



Repeat this experiment, but place one hand about 12 cm. above the 

 other. Obviously, the muscle sense is not well trained in the average 

 person. 



22. Sensation of Motion at the Elbow. Place the forearm upon a 

 board which it is possible to move, thereby imitating the flexion of the 

 forearm upon the arm. Close the eyes. While an assistant raises or 

 lowers the free end of the arm-board, state when you perceive a dis- 

 tinct motion of your forearm. How great an angular movement is 

 necessary in order to produce a sensation of motion? 



23. Paradoxic Resistance. Fasten a weight to a string about 2 m. 

 in length. Close your eyes and grasp the string anywhere, suspending 

 the weight in space. Quickly lower the weight upon a felt cushion. 

 When contact is made a definite sensation of resistance arises, as if the 

 hand were supported by a rod. 



